Paper.



r FFIQE,

JAMES E. BAUM, JR., OF CHICAGO, ILLINbIS.

Patented June 19, 1917.

PAPER.

1,230,095 Specification of Letters Patent. No Drawing. Application filedFebruary 11, 1916. Serial No. 77,602.

To all whom it may concern:

Be it known that I, JAMES E. BAUM, J r., a citizen of the United States,and resident of Chicago, county of Cook and State of Illinois,'haveinvented an Improvement in Paper, of which the following is aspecification.

The object of my invention is to provide ,an improved paper having itssurface coated or otherwise formed with a special compound which willenable the calendered paper to have a very smooth, dead or flat finishmaking it beautiful in texture, capable of receiving printed impressionsfrom half-tone Work of the finest mesh, and restful to the eyes whenemployed in books and reading matter generally.

Heretofore, it has been customary to coat the paper with a filler orloading of kaolin, known as pipe clay and china clay, the same beingessentially silicate of alumina. In practice, these substances have beendissolved in Water'and with animal sizing or casein to the consistenceof a creamy liquid, with or without coloring matter and applied to thesurface or surfaces of the paper and, after drying, subjected tocal'endering to give finish. Such papers, while having a fine finish,have a very high luster or gloss and hence are more or lessobjectionable for many uses.

In some cases the paper stock in the beaters is loaded with'the fillerwhich is beaten up and incorporated with the paper stock being treatedbefore it is fed to the paper mill proper. The loading material in thesecases has usually been sulfate of lime and kaolin and sometimesinfusorial earth, but the finished paper in these cases as in the other,receives more or less gloss when passed through the calendering rolls.

I have found that, if the paper web is coated or loaded with relativelypure silica, (that is, uncombined and hence differing from silicates)such as produced as an impalpable powder from pulverized white sand orquartz (which may be produced in a tube mill), associated with asuitable binder or size, the surface of the calendered paper may be of asmooth dead or flat finish, capable of receiving perfect imprints fromthe finest half-tone engravings and imparting the most artistic effectto the printed matter.

In carrying my lnvention into practice, the paper web may be coated withmy imings and dryings may be done before any calenderlng. So far asthese steps are concerned, any of the usual procedures may be followedand conducted with the machinery and appliances in common use.

The coating material or compound consists essentially of silica in suchfine subdivision as to be air-floated, water-floated or impalpable andhence substantially free from grit, associated with suflicient water andanimal size or, casein to give a creamy liquid consistency which may beeasily applied to the traveling web of paper. This is usually applied bythe present methods in use when using the kaolin compounds, and hence node ailed description of the apparatus will be necessary.

After the paper web has been coated on oneside, it is conveyed throughthe drying room in loops by traveling bars,as customary; and when dried,the web is passed through the .calendering rolls.

In some cases the coating is only upon one surface of the web, but ifboth sides of the paper are to be coated, then, before or after thecalendering operation, the dried paper web is returned and subjected toa coating operation on its other side, or the operation may be continuedwith a second set of coating and drying apparatus. After the secondcoating, -the paper web is subjected to the calendering operation and isthen ready for the market.

If white sand (uncombined) is employed in the preparation of the silicapowder, the coating compound will give a very white finish, but this maybe varied to suit any color or tint desiredby incorporating into thecreamy liquid the coloring matter desired. It is also evident that acolored sand, such as contains oxid of iron, might be used to provide apale yellow or ocher tint,and in such case no additional coloring matterthan the iron present need be added.

this respect. I may mix any desired quantities of-kaolin or otherpowdered material suitable for coating, with the powder-e silica andthereby obtain varying degrees of finely powdered uncombined'silica' maybe employed with the sizing in the paper stool; before being fed to thefourdrinier of the paper making machine, in which case the silica willconstitute a loading or give body to the fiber of the stock; and if theloading is in sufficient quantity, the calendered paper so made may beemployed without the additional surface coating above described. Broadlyconsidered, my invention 'comprehends the incorporation with the paperof the silica powder held in place by a suitable sizeor binder, whetherthis is accomplished simply as a coating or incorporated into the bodyas loading and applied to the paper stock in the beating engine, orotherwise, preliminary to the formation of the web.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is

1. As an article of manufacture, paper in sheet or web form having a.coating of uncombined silica in a state of impalpable 40 impalpablepowder mixed with clay in such proportions as to impart a moderatedegree of gloss and a very smooth surface.

4:. As an article of manufacture, paper in sheet or web form coated witha compound composed essentially of uncombined silica in a state ofimpalpable powder mixed with a coloring matter and suflicient size toact as a binder between the materials and with the fiber and form a verysmooth surface.

5. As an article of manufacture, paper having its fiber associated withimpalpable powder, of uncombined silica, and calendered to a smoothsurface.

6. As an article of manufacture, paper in sheets or web form having itssurface provided with an impalpable powder of uncombined silica held inplace by size, and calendered to a smooth surface.

In testimony of which invention, I here unto set my hand.-

JAMES E. BAUM, JR.

Witnesses:

R. M. HUNTER, FLORENCE DEACON.

